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IAU Symposium 285, New Horizons in Time-Domain Astronomy, gave a comprehensive overview of the status quo in 2011, exploring, astronomical variability at both Galactic and extragalactic distances. Several years later, IAU Symposium 339 witnessed a new level of activity and planning, with ambitious instruments that add a new dimension to some of those current in 2011 and ingenious methodology in the emerging field of astroinformatics. Major new instruments, whose output dwarfs those previously available, and analysis techniques that could not have been implemented until very recently, are being coupled with a broadening diversity in wavelengths. IAU S339 introduces the rich potential for new techniques for both analysis and communication, while covering the basic fundamentals such as data quality, standardization and archive access. Many early-career scientists are already central players in these projects: time-domain astronomy is the future and in their hands may it flourish and grow.
The rocky shores of the north-east Atlantic have been long studied. Our focus is from Gibraltar to Norway plus the Azores and Iceland. Phylogeographic processes shape biogeographic patterns of biodiversity. Long-term and broadscale studies have shown the responses of biota to past climate fluctuations and more recent anthropogenic climate change. Inter- and intra-specific species interactions along sharp local environmental gradients shape distributions and community structure and hence ecosystem functioning. Shifts in domination by fucoids in shelter to barnacles/mussels in exposure are mediated by grazing by patellid limpets. Further south fucoids become increasingly rare, with species disappearing or restricted to estuarine refuges, caused by greater desiccation and grazing pressure. Mesoscale processes influence bottom-up nutrient forcing and larval supply, hence affecting species abundance and distribution, and can be proximate factors setting range edges (e.g., the English Channel, the Iberian Peninsula). Impacts of invasive non-native species are reviewed. Knowledge gaps such as the work on rockpools and host–parasite dynamics are also outlined.
The first ultraviolet photochemical oxidation (UVox) extraction method for marine dissolved organic carbon (DOC) as CO2 gas was established by Armstrong and co-workers in 1966. Subsequent refinement of the UVox technique has co-evolved with the need for high-precision isotopic (Δ14C, δ13C) analysis and smaller sample size requirements for accelerator mass spectrometry radiocarbon (AMS 14C) measurements. The UVox line at UC Irvine was established in 2004 and the system reaction kinetics and efficiency for isolating seawater DOC rigorously tested for quantitative isolation of ∼1 mg C for AMS 14C measurements. Since then, improvements have been made to sampling, storage, and UVox methods to increase overall efficiency. We discuss our progress, and key UVox system parameters for optimizing precision, accuracy, and efficiency, including (1) ocean to reactor: filtration, storage and preparation of DOC samples, (2) cryogenic trap design, efficiency and quantification of CO2 break through, and (3) use of isotopic standards, blanks and small sample graphitization techniques for the correction of DOC concentrations and Fm values with propagated uncertainties. New DOC UVox systems are in use at many institutions. However, rigorous assessment of quantitative UVox DOC yields and blank contributions, DOC concentrations and carbon isotopic values need to be made. We highlight the need for a community-wide inter-comparison study.
Although dicamba-resistant crops can provide an effective weed management option, risk of dicamba off-site movement to sensitive crops is a concern. Previous research with indeterminate soybean identified 14 injury criteria associated with dicamba applied at V3/V4 or R1/R2 at 0.6 to 280 g ae ha−1. Injury criteria rated on a 0 to 5 scale (none to severe), along with percent visible injury and plant height reduction, and canopy height collected 7 and 15 d after treatment (DAT) were analyzed using multiple regression with a forward-selection procedure to develop yield prediction models. Variables included in the 15 DAT models (in order of selection) for V3/V4 were lower stem base lesions/cracking, plant height reduction, terminal leaf epinasty, leaf petiole droop, leaf petiole base swelling, and stem epinasty, whereas for R1/R2 variables were lower stem base lesions/cracking, terminal leaf chlorosis, leaf petiole base swelling, stem epinasty, terminal leaf necrosis, and terminal leaf cupping. To validate the models, experiments including the same dicamba rates and application timings used in previous research were conducted at two locations. For the variables specific to each model, data collected for the dicamba rates were used to predict yield. For the V3/V4 15 DAT model, predicted yield reduction (compared with the nontreated control for dicamba at 0.6 to 4.4 g ha−1) underestimated or overestimated observed yield reduction by an average of 1 and 3 percentage points. For 8.8 g ha−1, predicted yield reduction overestimated observed yield reduction by 8 points and for 17.5 g ha−1 by 20 points. For the R1/R2 15 DAT model, predicted yield reduction for 0.6 to 4.4 g ha−1 overestimated observed yield reduction by an average of 3 to 5 percentage points. For dicamba at 8.8 g ha−1, predicted yield reduction underestimated observed yield reduction by 8 points and for 17.5 g ha−1 overestimated by 6 points.
With the recent discovery of a dozen dusty star-forming galaxies and around 30 quasars at z > 5 that are hyper-luminous in the infrared (μ LIR > 1013 L⊙, where μ is a lensing magnification factor), the possibility has opened up for SPICA, the proposed ESA M5 mid-/far-infrared mission, to extend its spectroscopic studies toward the epoch of reionisation and beyond. In this paper, we examine the feasibility and scientific potential of such observations with SPICA’s far-infrared spectrometer SAFARI, which will probe a spectral range (35–230 μm) that will be unexplored by ALMA and JWST. Our simulations show that SAFARI is capable of delivering good-quality spectra for hyper-luminous infrared galaxies at z = 5 − 10, allowing us to sample spectral features in the rest-frame mid-infrared and to investigate a host of key scientific issues, such as the relative importance of star formation versus AGN, the hardness of the radiation field, the level of chemical enrichment, and the properties of the molecular gas. From a broader perspective, SAFARI offers the potential to open up a new frontier in the study of the early Universe, providing access to uniquely powerful spectral features for probing first-generation objects, such as the key cooling lines of low-metallicity or metal-free forming galaxies (fine-structure and H2 lines) and emission features of solid compounds freshly synthesised by Population III supernovae. Ultimately, SAFARI’s ability to explore the high-redshift Universe will be determined by the availability of sufficiently bright targets (whether intrinsically luminous or gravitationally lensed). With its launch expected around 2030, SPICA is ideally positioned to take full advantage of upcoming wide-field surveys such as LSST, SKA, Euclid, and WFIRST, which are likely to provide extraordinary targets for SAFARI.
Measurements in the infrared wavelength domain allow direct assessment of the physical state and energy balance of cool matter in space, enabling the detailed study of the processes that govern the formation and evolution of stars and planetary systems in galaxies over cosmic time. Previous infrared missions revealed a great deal about the obscured Universe, but were hampered by limited sensitivity.
SPICA takes the next step in infrared observational capability by combining a large 2.5-meter diameter telescope, cooled to below 8 K, with instruments employing ultra-sensitive detectors. A combination of passive cooling and mechanical coolers will be used to cool both the telescope and the instruments. With mechanical coolers the mission lifetime is not limited by the supply of cryogen. With the combination of low telescope background and instruments with state-of-the-art detectors SPICA provides a huge advance on the capabilities of previous missions.
SPICA instruments offer spectral resolving power ranging from R ~50 through 11 000 in the 17–230 μm domain and R ~28.000 spectroscopy between 12 and 18 μm. SPICA will provide efficient 30–37 μm broad band mapping, and small field spectroscopic and polarimetric imaging at 100, 200 and 350 μm. SPICA will provide infrared spectroscopy with an unprecedented sensitivity of ~5 × 10−20 W m−2 (5σ/1 h)—over two orders of magnitude improvement over what earlier missions. This exceptional performance leap, will open entirely new domains in infrared astronomy; galaxy evolution and metal production over cosmic time, dust formation and evolution from very early epochs onwards, the formation history of planetary systems.
Research conducted in the field identified 14 injury criteria associated with dicamba (Clarity® diglycolamine salt) applied at 0.6 to 280 g ae ha–1 (1/1,000 to 1/2 of 560 g ha–1 use rate) to indeterminate soybean at V3/V4 or R1/R2. For each criterion, injury was rated using a scale of 0=no injury, 1=slight, 2=slight to moderate, 3=moderate, 4=moderate to severe, and 5=severe. Greatest crop injury 15 d after treatment (DAT) was observed for dicamba rates of 0.6 to 4.4 g ha–1 for upper canopy pale leaf margins (3.8 to 4.2) at V3/V4 and for terminal leaf cupping (4.1 to 5.0) at R1/R2, and for rates of 0.6 to 8.8 g ha–1 for upper canopy leaf cupping (3.8 to 4.8) and upper canopy leaf surface crinkling (3.4 to 4.4) at V3/V4. Injury 15 DAT was equivalent to the nontreated control for dicamba rates as high as 4.4 g ha–1 for lower stem base swelling at V3/V4 and for upper canopy leaf rollover/inversion and terminal leaf necrosis at R1/R2; for rates as high as 8.8 g ha–1 for leaf petiole base swelling and stem epinasty at R1/R2, and lower stem base lesions/cracking (V3/V4 and R1/R2 average); and for rates as high as 17.5 g ha–1 for lower leaf soil contact at V3/V4 and leaf petiole droop at R1/R2. The response to increasing dicamba rate observed for the injury criteria was in contrast to the steady increase in visual injury and plant height reduction rated as 0 to 100%. The moderate to severe upper canopy leaf cupping, pale leaf margins, and leaf surface crinkling, and terminal leaf cupping 15 DAT with dicamba at 0.6 to 4.4 g ha–1 corresponded to soybean yield loss of 1% to 9% for application at V3/V4 and 2% to 17% at R1/R2.
Background:ATP8A2 mutations have only recently been associated with human disease. We present the clinical features from the largest cohort of patients with this disorder reported to date. Methods: An observational study of 9 unreported and 2 previously reported patients with biallelic ATP8A2 mutations was carried out at multiple centres. Results: The mean age of the cohort was 9.4 years old (range: 2.5-28 yrs). All patients demonstrated developmental delay, severe hypotonia and movement disorders: chorea/choreoathetosis (100%), dystonia (27%) or facial dyskinesia (18%). Hypotonia was apparent at birth (70%) or before 6 months old (100%). Optic atrophy was observed in 75% of patients who had a funduscopic examination. MRI of the brain was normal for most patients with a small proportion showing mild cortical atrophy (30%), delayed myelination (20%) and/or hypoplastic optic nerves (20%). Epilepsy was seen in two older patients. Conclusions:ATP8A2 gene mutations have emerged as a cause of a novel phenotype characterized by developmental delay, severe hypotonia and hyperkinetic movement disorders. Optic atrophy is common and may only become apparent in the first few years of life, necessitating repeat ophthalmologic evaluation. Early recognition of the cardinal features of this condition will facilitate diagnosis of this disorder.
We report marine dissolved organic carbon (DOC) ∆14C from seawater collected from the North central Pacific Ocean (NCP) in 2015. These measurements show DOC ∆14C values averaged –235±5‰ (n=3) in the mixed layer (24–81 m) and –544±5‰ (n=5) in the deep water (1500–5139 m). A comparison of these data with two previously published DOC ∆14C profiles from the NCP in 1985 and 1987 reveals that deep DOC ∆14C values have decreased. We discuss several possible mechanisms that could cause such a shift in DOC ∆14C values, including spatial inhomogeneity and temporal variability due to changes in the dissolution and ∆14C value of surface derived particles in the deep sea. We find that forthcoming profiles of DOC ∆14C results from the NCP will determine the primary mechanisms controlling deep DOC ∆14C distributions, and changes over the past three decades.
We report ∆14C measurements of cellulose extracted from near monthly tree ring growth for the 1960s of a white oak that grew in western Oregon, USA. Comparison with ∆14C measurements of atmospheric CO2 reveals that the tree ring ∆14C values were equal to or lower than those in atmospheric CO2 at the time of ring formation. We suggest that the low tree ring ∆14C values during the period 1962–1963 were caused by the presence of an atmospheric front or blocking between subpolar and temperate air masses that delayed the arrival of the bomb signal at the tree’s site.
The Hubble Source Catalog (HSC) combines lists of sources detected on images obtained with the WFPC2, ACS and WFC3 instruments aboard the Hubble Space Telescope (HST) and now available in the Hubble Legacy Archive. The catalogue contains time-domain information for about two million of its sources detected using the same instrument and filter on at least five HST visits. The Hubble Catalog of Variables (HCV) aims to identify HSC sources showing significant brightness variations. A magnitude-dependent threshold in the median absolute deviation of photometric measurements (an outlier-resistant measure of light-curve scatter) is adopted as the variability detection statistic. It is supplemented with a cut in χred2 that removes sources with large photometric errors. A pre-processing procedure involving bad image identification, outlier rejection and computation of local magnitude zero-point corrections is applied to the HSC light-curves before computing the variability detection statistics. About 52 000 HSC sources have been identified as candidate variables, among which 7,800 show variability in more than one filter. Visual inspection suggests that ∼70% of the candidates detected in multiple filters are true variables, while the remaining ∼30% are sources with aperture photometry corrupted by blending, imaging artefacts or image processing anomalies. The candidate variables have AB magnitudes in the range 15–27m, with a median of 22m. Among them are the stars in our own and nearby galaxies, and active galactic nuclei.
HR 6902 was the first target of a systematic study by Griffin (1986, JApA, 7, 195) of binaries showing composite spectra. It is also a well-studied member of the ζ Aur class. ζ Aur systems are long-period eclipsing binaries that are comprised of an evolved giant primary and a hot dwarf companion. Although those component stars have very different effective temperatures they have similar luminosities in the blue and near-UV regions, and hence display a composite spectrum at those wavelengths. In principle the ζ Aur systems are excellent tests of evolutionary and structural stellar models. In recent years the somewhat fragmentary eclipse photometry of HR 6902 has been out-classed by the high-precision continuous monitoring by the space mission CoRoT. HR 6902 was selected as a primary target of its seismology field, because the possible detection of solar-like pulsations in a giant component of a double-lined eclipsing binary could help to calibrate the scaling relation of giant pulsators. Our poster reported the results of a new analysis based on the CoRoT observations and follow-up spectroscopy with HARPS at the ESO 3.6-m telescope at La Silla.
The unprecedented accuracy of the CoRoT photometry enabled us to:
improve drastically the accuracy of the binary orbit and stellar parameters (by a factor ~10 for the radii)
extend the test of validity/calibration of the scaling relations to high stellar mass and radius, and put constraints on the evolutionary state (particularly since this binary is certainly free from tidal effects).
In the last decade great strides have been made in understanding the role of binary stars in the evolution and shaping of planetary nebulæ (PNe). Observational efforts have mainly focused on finding close binaries with orbital periods of 1 day or less. Those close binary systems make up around 1 in 5 PNe, and constitute the youngest accessible window into the aftermath of the critical and unobserved common-envelope (CE) phase of binary-star evolution. The poster focused on our recent work with the High Resolution Spectrograph (HRS) on the Southern African Large Telescope (SALT) to search for long-period binaries in PNe. Considerably less is known about such long-period binaries with orbital periods of weeks to years, but they may be fundamental to improving CE population synthesis models and for determining the total binary fraction of PNe. The queue-mode operation of SALT and the excellent sensitivity and stability of HRS (which is enclosed in a vacuum tank) are ideally suited to detecting binaries with low radial-velocity amplitudes over the expected timescales of weeks to years. Many exciting new discoveries about binaries have already been made in this newly-accessible southern horizon in time-domain astronomy thanks to the many unique advantages of SALT.
We have identified a new population of luminous, optical, narrow-lined transients (FWHM ∼1000 km s−1) coincident with the nuclear region of Seyfert galaxies. According to extensive spectrophotometric follow-ups of the main event (PS1-10adi), we could exclude both normal active galactic nucleus activity and changing-look quasars as the origin. The integrated energy output and spectral evolution over a time-scale of several years point to two possible paths of origin: a tidal disruption of a star by a supermassive black hole, or an extremely energetic supernova occurring within the Seyfert galaxy’s narrow-line (or broad-line) region. The former model would require invoking a specific variant of a tidal disruption, while the latter would require an extremely efficient conversion of kinetic energy via shock interaction between the supernova ejecta and the dense ambient medium.